“The Department cannot confirm if this whale is the same individual that was spotted entangled off the Gapsé Peninsula at the end of August. The entangled right whale originally sighted has not been seen since it was first reported on Monday August 28. Flights and boats were sent out and were unable to relocate the whale,” The DFO said in a statement Friday night.

To date there has been only 11 confirmed North Atlantic Right whale deaths in the Gulf of St. Lawrence. Two other whale carcasses have appeared off the coast of New England, bringing the total to 13.

The DFO says they’ll attempt to retrieve the carcass and perform a necropsy next week.

The deaths of the 13 whales have been deemed an Unusual Mortality Event – or a significant die-off in a population – by the United States’ National Oceanic and Atmospheric Administration (NOAA) and has prompted both Canada and the U.S. to launch a joint investigation.

“Thirteen animals is a lot of animals when you’re talking about a population of less than 500,” said Sean Hayes, of the NOAA in August. “It’s anywhere from two to three per cent of the entire population.”

Conservation groups and marine scientists have said the high number of accidental deaths this year threaten the survival of the species.

Two more North Atlantic right whales found dead off coast of Newfoundland

Before 2017, deaths of right whales were fairly uncommon with only 3.8 deaths per year on average.

The right whales, which summer off of New England and Canada, are among the most imperilled marine mammals on Earth as populations have only slightly rebounded from the whaling era, when they nearly became extinct.